1 files changed, 11 insertions, 2 deletions
diff --git a/source/blender/makesdna/DNA_mesh_types.h b/source/blender/makesdna/DNA_mesh_types.h
index bf50100b302..24f3d1c95ed 100644
--- a/source/blender/makesdna/DNA_mesh_types.h
+++ b/source/blender/makesdna/DNA_mesh_types.h
@@ -132,14 +132,23 @@ typedef struct Mesh_Runtime {
    */
   char wrapper_type_finalize;
 
+  int subsurf_resolution;
   /**
    * Settings for lazily evaluating the subdivision on the CPU if needed. These are
    * set in the modifier when GPU subdivision can be performed.
    */
   char subsurf_apply_render;
   char subsurf_use_optimal_display;
-  char _pad[2];
-  int subsurf_resolution;
+
+  /**
+   * Caches for lazily computed vertex and polygon normals. These are stored here rather than in
+   * #CustomData because they can be calculated on a const mesh, and adding custom data layers on a
+   * const mesh is not thread-safe.
+   */
+  char vert_normals_dirty;
+  char poly_normals_dirty;
+  float (*vert_normals)[3];
+  float (*poly_normals)[3];
 
   void *_pad2;